10.25.11 11:10 PM ET

Herman Cain, the multimillionaire businessman who has made tax fairness a central part of his surging presidential campaign, missed paying his state income taxes for 2006 while undergoing treatment for cancer, prompting Georgia to file a tax lien against him that wasn’t settled until late 2008, according to documents reviewed by The Daily Beast.

The Republican’s campaign late Tuesday confirmed the lien, portraying the unpaid taxes as an oversight while Cain was undergoing cancer treatment and the state’s lien as an excessive response that shows the need for tax reform.

“The experience serves as an example of how broken our federal and state bureaucracies are with respect to the collection of revenue,” Cain campaign spokesman J.D. Gordon told The Beast. “The entire process is driven by automated letters generated in response to deadlines.”

Cain is a multimillionaire who ran the Godfather’s Pizza chain before dabbling in politics. His long-shot campaign for the GOP presidential nomination is now surging on the strength of his charismatic performances during the early debates and public intrigue with his 9-9-9 tax plan, which would replace the current tax code with a flat 9 percent income tax, a 9 percent corporate tax, and a 9 percent national sales tax. A CBS/New York Times poll Tuesday showed Cain leading former frontrunner Mitt Romney.

According to court documents obtained by The Beast, Cain and his wife, Gloria, were served in February 2008 with a tax lien totaling $8,558.46 for unpaid income taxes and penalty due for the 2006 calendar year.

Gordon said Cain had filed with the IRS and won a six-month reprieve in paying his 2006 federal taxes as he was undergoing his treatment for stage four lymphoma and believed that filing should also have bought him time with the state of Georgia. “In Georgia, a taxpayer can submit a copy of his federal extension to request an extension of state income taxes,” Gordon said.

But instead, the state sent a notice of overdue taxes in October 2007, and then proceeded with the tax lien four months later, he said.

Cain’s accountant fought the Georgia Department of Revenue on behalf of his client well into 2008 and the two sides finally settled the matter in November 2008. A court formally withdrew the state tax lien on Dec. 8, 2008, court records show.

Gordon said the campaign was researching the exact date on which Cain made the payment to extinguish the lien.

Georgia revenue officials declined to comment on the matter except to say the lien was withdrawn.